Craig Whitfield spent years in restaurant dining rooms and bars. Not as a customer, however. As an investigator.In the 10 years he worked as director of safety and security for one of the nation’s largest restaurant franchise companies, the Mishawaka native watched bartenders pocket profits and servers help themselves to more than their tips.

He saw servers delete entire meals from point-of-sales systems and pocket the money. He caught a bartender who had stolen $40,000 from a restaurant over five years by not always ringing in what customers had ordered to drink.

He describes helping Ohio police arrest a waitress at a national chain restaurant after she admitted to inflating her tips on credit card transactions several years ago. She stole more than $200 over five months from customers, including Whitfield when he posed as a customer and she doubled her $3 tip on his credit card.

“Most restaurant employees are honest, hardworking people. Unfortunately, the dishonest employees cast a bad light on the good ones,” Whitfield says. “When they get greedy, that’s when they hit the radar.”Employee theft costs U.S. restaurants 4 to 5 percent in sales each year. The National Restaurant Association estimates that employee theft accounts for 75 percent of a restaurant’s inventory losses.“With a million restaurants and bars across the country,” he says, “this loss is enormous.”

And the problem does not center around one brand or concept. It can affect any restaurant, anywhere, family owned or chain, 50 seats or 250 seats.“Yes, it even happens here. We have a lot of restaurants,” Whitfield says. “It’s an industry where there’s easy access to cash, and thieves are thieves, no matter the restaurant.”Whitfield has worked in law enforcement for most of his life. He spent 25 years with the Mishawaka Police Department working as an investigator. Not long after he retired, he decided to join the Memorial Hospital police department, where he currently serves as assistant chief.

He draws on a decade of experience investigating internal theft at restaurants in his book, “Guess Who’s Eating Your Profits: The Manager’s Essential Guide to Restaurant and Bar Loss Prevention and Investigations.” The book serves as a guide to restaurateurs, offering advice about how to identify, investigate and prosecute employees who might be stealing from their business.“So many mom-and-pop restaurants and shops go under,” he says, “and the ones that do, often have theft going on in some fashion.”

His own mother and father, who owned the G & L Diner in the mid-’80s at the corner of Mishawaka Avenue and Division Street in Mishawaka, caught a server stealing from them.“She was throwing the meal ticket away and pocketing the money,” he remembers. “I learned that just because the person is your friend, and they treat you nice, you can’t close your eyes to the fact that if your numbers are off, someone might be stealing from you.”

Cases of restaurant theft don’t always make newspaper headlines, because restaurateurs often try to deal with the situation in-house.“But if you’re not wise to all the ways there are to steal, and you don’t know how to push back on an employee who denies wrongdoing, you’re set up for a tough investigation on your own,” he says.In some cases, the crime can even affect restaurant diners who hand their server a credit or debit card. Whitfield offers consumers this advice:

• Protect your credit card. If it is taken from the table to complete the transaction, make sure the server returns your card. Sometimes a card can be swapped with a lookalike, which is usually a card left behind by another guest and was subsequently canceled,• Track your dining purchases. Keep your receipts. Leaving a receipt behind sends a message to the server that you really don’t care. Your copy serves as a reminder to check the transaction against your bank draw. You can confirm the amount is what you actually authorized.• Speak to a manager when you discover irregularities on your check.“Guess Who’s Eating Your Profits...” is available at Barnes & Noble book sellers and Amazon. Hardcover costs $28.95 and softcover is $19.95.